Method of preparing naphthalocyanines

Abstract

A method of preparing a naphthalocyanine is provided. The method comprises the steps of: (i) providing a tetrahydronaphthalic anhydride; (ii) converting said tetrahydronaphthalic anhydride to a benzisoindolenine; and (iii) macrocyclizing said benzisoindolenine to form a naphthalocyanine.

1. A method of preparing a naphthalocyanine comprising the steps of:
 (i) providing a tetrahydronaphthalic anhydride of formula (I): 
 
       
         
           
           
               
               
           
         
         (ii) converting said tetrahydronaphthalic anhydride to a benzisoindolenine of formula (II): 
       
       
         
           
           
               
               
           
         
         (iii) macrocyclizing said benzisoindolenine to form a naphthalocyanine of formula (III): 
       
       
         
           
           
               
               
           
         
       
       wherein: 
       R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 , R 9 , R 10 , R 11 , R 12 , R 13 , R 14 , R 15  and R 16  are each independently selected from hydrogen, hydroxyl, C 1-20  alkyl, C 1-20  alkoxy, amino, C 1-20  alkylamino, di(C 1-20  alkyl)amino, halogen, cyano, thiol, C 1-20  alkylthio, nitro, C 1-20  alkylcarboxy, C 1-20  alkylcarbonyl, C 1-20  alkoxycarbonyl, C 1-20  alkylcarbonyloxy, C 1-20  alkylcarbonylamino, C 5-20  aryl, C 5-20  arylalkyl, C 5-20  aryloxy, C 5-20  arylalkoxy, C 5-20  heteroaryl, C 5-20  heteroaryloxy, C 5-20  heteroarylalkoxy or C 5-20  heteroarylalkyl; 
       M is absent or selected from Si(A 1 )(A 2 ), Ge(A 1 )(A 2 ), Ga(A 1 ), Mg, Al(A 1 ), TiO, Ti(A 1 )(A 2 ), ZrO, Zr(A 1 )(A 2 ), VO, V(A 1 )(A 2 ), Mn, Mn(A 1 ), Fe, Fe(A 1 ), Co, Ni, Cu, Zn, Sn, Sn(A 1 )(A 2 ), Pb, Pb(A 1 )(A 2 ), Pd and Pt; 
       A 1  and A 2  are axial ligands, which may be the same or different, and are selected from OH, halogen or OR q ; 
       R q  is selected from C 1-16  alkyl, C 5-20  aryl, C 5-20  arylalkyl, C 1-20  alkylcarbonyl, C 1-20  alkoxycarbonyl or Si(R x )(R y )(R z ); and 
       R x , R y  and R z  may be the same or different and are selected from C 1-20  alkyl, C 5-20  aryl, C 5-20  arylalkyl, C 1-20  alkoxy, C 5-20  aryloxy or C 5-20  arylalkoxy. 
     
     
       2. The method of  claim 1 , wherein R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 , R 9 , R 10 , R 11 , R 12 , R 13 , R 14 , R 15  and R 16  are all hydrogen. 
     
     
       3. The method of  claim 1 , wherein step (ii) comprises a one-pot conversion from the tetrahydronaphthalic anhydride of formula (I) to a salt of the benzisoindolenine of formula (II). 
     
     
       4. The method of  claim 3 , wherein said salt is a nitrate salt. 
     
     
       5. The method of  claim 3 , wherein said one-pot conversion is effected by heating with a reagent mixture comprising ammonium nitrate. 
     
     
       6. The method of  claim 5 , wherein said reagent mixture comprises at least 2 equivalents of ammonium nitrate with respect to said tetrahydronaphthalic anhydride of formula (I). 
     
     
       7. The method of  claim 5 , wherein said reagent mixture comprises urea. 
     
     
       8. The method of  claim 5 , wherein said reagent mixture comprises at least one further ammonium salt. 
     
     
       9. The method of  claim 8 , wherein said at least one further ammonium salt is selected from the group consisting of: ammonium sulfate and ammonium benzenesulfonate. 
     
     
       10. The method of  claim 5 , wherein said reagent mixture comprises ammonium molybdate. 
     
     
       11. The method of  claim 5 , wherein said heating is within a temperature range of 150 to 200° C. 
     
     
       12. The method of  claim 11 , wherein said heating is in the presence of a solvent selected from the group consisting of: nitrobenzene, diphenyl, diphenyl ether, mesitylene, anisole, phenetole, dichlorobenzene, trichlorobenzene and mixtures thereof. 
     
     
       13. The method of  claim 3 , wherein the benzisoindolenine of formula (II) is liberated from the benzisoindolenine salt using sodium methoxide. 
     
     
       14. The method of  claim 1 , wherein M is Ga(A 1 ). 
     
     
       15. The method of  claim 1 , wherein step (iii) comprises heating said benzisoindolenine of formula (II) in the presence of GaCl 3 .